Convergent, Divergent or Co- evolution?!

Honeyguides

Macroevolution

Since the first single- celled life began on Earth, life has taken amazing and unique forms – Ourselves included We can trace the large- scale processes of evolution through phylogeny

Macroevolution Macroevolution: Large- scale evolutionary changes including the formation of new species and taxa We can examine this to study evolutionary relationships between species

The Beginning of Life Regardless of how different species are, there was a first species we all evolved from – A single-celled organism How did this first cell arise? – How did organic matter first appear?

Abiogenesis Abiogenesis: The formation of life from non-organic material many of the building blocks of life can be formed under natural conditions – Amino acids, hydrocarbon chains Some have even been found within comets

Abiogenesis We know that the elements of life can form naturally Scientists have not yet fully recreated the exact environmental conditions that existed billions of years ago

Abiogenesis Theories It is believed that life has existed on Earth for 3.5 billion years – 2 billion years later, eukaryotic cells evolved – Several more hundred million years later, multicellular organisms appeared

Cambrian Explosion Cambrian Explosion: a period of time in which the evolution of most major animal phyla occurred over 40 million years One of the most significant periods of evolution in Earth’s history

Rise of the Dinosaurs 250 million years ago, dinosaurs first appeared By 200 million years ago, they truly ruled the earth At their height, dinosaurs were an amazingly diverse group

End of the Dinosaurs For all their success, dinosaurs were wiped out 65 million years ago – At least 300 species went extinct when a 200 km wide asteroid collided with Earth Although the loss of life was devastating, this was not the only (or the largest) mass extinction in Earth’s history

Mass Extinction There have been many mass extinctions in history, the largest of which occurred 251 million years ago in the Permian Era Most life was wiped out in this extinction – 90% of all marine life This event eventually gave rise to dinosaurs

Consequences of Extinction How different would the Earth be today if these extinctions had not occurred? Gene pools have shrunk, shifted, and been altered These extinctions have led to genetic drift on a massive scale

Extinctions Today We are in the midst of another mass extinction today Species are disappearing today at an enormous rate Humans, and the impact we have on Earth, are the cause